Effect of calcination temperature on structure of silica doped on zirconia for photodegradation of 2-chlorophenol

Simple microwave assisted method was employed to prepare silica (SiO2) doped zirconia (ZrO2) that synthesized under different calcination temperature which are 350, 550 and 850 °C and denoted as Si/ZrO2-350, Si/ZrO2-550 and Si/ZrO2-850, respectively for photodegradation of 2-chlorophenol (2-CP). The synthesized catalysts were characterized by X-ray diffraction, Fourier transform infrared and ultraviolet-visible diffuse reflectance spectroscopy. The results showed that higher calcination temperature and the presence of Si induced the tetragonal phase of ZrO2 as well as narrowed the band gap energy, which affected the photocatalytic activity. The catalyst was subsequently tested for the photocatalytic activity on 2-CP degradation under various parameters such as pH, catalyst dosage and initial concentration of 2-CP under visible light irradiation. Si/ZrO2-850 showed the highest photodegradation of 2-CP due to presence of tetragonal phase on ZrO2 that resulting stabilize the structure. The photocatalytic performance of the catalysts towards degradation of 10 mgL of 2-CP at pH 3 and 0.125 g L catalyst under visible light after 240 minutes as following order: Si/ZrO2-850 (88%) > Si/ZrO2550 (65%) > Si/ZrO2350 (57%) > ZrO2-850 (37%). The photodegradation followed the pseudofirst order Langmuir-Hinshelwood kinetic model. This study demonstrated that the Si/ZrO2 has a potential to be used in photocatalytic degradation of various organic pollutant.